This invention relates to electrochemical power sources and, more particularly, to rechargeable batteries that include solid electrolytes.
Considerable efforts have been directed to the development of rechargeable batteries that include solid rather than liquid electrolytes. A solid-electrolyte battery exhibits practical advantages such as freedom from fluid leakage. But the solid electrolyte included in some batteries as heretofore constructed possesses low ionic conductivity. Solid electrolytes with higher conductivity have been developed for the alkali metal ions, e.g., sodium and lithium, but electrodes of sodium or lithium show undesirable characteristics such as high reactivity with air. Thus, for example, a battery that includes a lithium-based solid electrolyte and a lithium electrode must be sealed to prevent the occurrence of potentially hazardous reactions between the electrode and air.
Accordingly, efforts have continued by workers skilled in the art aimed at trying to develop other solid-electrolyte batteries. In particular, these efforts have concentrated on trying to develop a rechargeable solid-electrolyte battery that need not be sealed and is mechanically rugged. Also, for some applications of practical importance, it is advantageous that such a battery be capable of being fabricated in a thin-film form that is compatible with integrated-circuit device structures. Hence, this last-mentioned capability has often also been included as a goal of the development efforts.